Random matrix models generalize to Group Field Theories (GFT) whose Feynman
graphs are dual to gluings of higher dimensional simplices. It is generally
assumed that GFT graphs are always dual to pseudo manifolds. In this paper we
prove that already in dimension three (and in all higher dimensions), this is
not true due to subtle differences between simplicial complexes and gluings
dual to GFT graphs. We prove however that, fortunately, the recently introduced
"colored" GFT models [1] do not suffer from this problem and only generate
graphs dual to pseudo manifolds in any dimension